The present technology relates to a semiconductor device such as an image pickup device and to a semiconductor unit including the same.
In a solid-state image pickup apparatus such as a CCD (Image Coupled Device) image sensor and a CMOS (Complementary Metal Oxide Semiconductor) image sensor, as pixel size is reduced, the number of photons entering a unit pixel (solid-state image pickup device) is decreased, leading to lowered sensitivity and a lowered saturated charge amount.
Therefore, a method of obtaining three-color photoelectric conversion signals by one pixel by layering three photoelectric conversion sections has been proposed. For example, one of the three photoelectric conversion sections (such as a photoelectric conversion section corresponding to green color light) is arranged on a silicon substrate (semiconductor substrate), that is, outside the silicon substrate, while the remaining two photoelectric conversion sections (such as photoelectric conversion sections corresponding to red color light and blue color light) are provided inside the silicon substrate. In such an image pickup device, all incident photons are allowed to be used for photoelectric conversion, and therefore, image quality may be improved thereby.
However, in the image pickup device having a photoelectric conversion section outside the silicon substrate, charge is transferred from the photoelectric conversion section outside the silicon substrate to inside of the silicon substrate, and is accumulated therein. Therefore, there is a disadvantage that noise is generated at the time of the foregoing charge transfer (for example, Japanese Unexamined Patent Application Publication No. 2012-60076).